Synergistic Co/S co-doped CeO2 sulfur-oxide catalyst for efficient catalytic reduction of toxic organics and heavy metal pollutants under dark conditions

The rising accumulation of pollutants, including heavy metals and toxic organics, necessitates effective environmental remediation to protect health and biological systems. In this study, a cubic cerianite CeO 2 -like Co/S co-doped CeO 2 sulfur-oxide catalyst (labeled as CeCoOS) with super catalytic reduction performance of pollutants with NaBH 4 as a reducing agent under dark was prepared via a green and facile preparation method. Transition metal Co 2+ -cation and S 2− -anion co-doped CeO 2 adjusted the energy bandgap and introduced oxygen vacancy (Vo), which converted Ce 4+ around Vo into Ce 3+ to maintain electric neutrality. The heterovalent Ce 4+ /Ce 3+ states in Co/S-CeO 2 enhance the electron lifetime and facilitate fast electron transfer . The valence transition between Ce 4+ /Ce 3+ and Vo make the Co/S co-doped in CeO 2 catalyst increase its electrochemically active surface sites and accelerate the pollutants reduction reaction. The CeCoOS-3 with Co/S dopants has an excellent catalytic reduction activity to completely reduce 20 ppm toxic 4-NP in 10 min, 50 ppm organic dyes of MB, RhB, and MO in 6 min, and 50 ppm heavy metal Cr 6+ in 10 min. The CeCoOS-3 sulfur-oxide catalyst also exhibited excellent stability in the reusability test. Therefore, CeCoOS sulfur-oxide catalysts are expected to be used for dye decolorization, detoxification of organic toxins, and reduction of electroplating wastewater.